Slugs and snails are molluscs, feeding on a variety of plants and decaying plant matter. Slugs and snails move by means of a muscular foot which secretes mucus along which the animal glides. This mucus later dries to form the tell tale silvery slime trails. Snails lay approximately 80 round white eggs into holes or harbourages in the soil. Both slugs and snails need moisture and are most active at night or during cloudy and rainy days. On dry, sunny days snails shut themselves into their shells, sealing the entrance to keep moist. During cold weather slugs and snails hibernate in the topsoil.
How do I get rid of them?
Here are some practical ways to try and control slugs and snails in your garden and home:
- Eliminate sites where slugs and snails may hide during the day such as stones, debris or vegetation growing close to the ground.
- If you water infested areas of your garden in late afternoon you will encourage slugs and snails to come out. Searching the area at dusk and physically removing the slugs and snails can be a very effective form of control.
- Beer or milk baited traps are effective although their range is confined to only a few feet. A smooth glass or plastic container can be sunk into the soil and filled with beer or milk and the rim positioned1-2 cm above the soil's surface; slugs can crawl up and over the rim and fall into the trap. This technique is best used on a small scale to protect a group of choice plants as the milk or beer has to be replenished every few days and there needs to be a number of traps positioned for this to be effective.
- Barriers comprising of sand, ash, gravel, broken eggshells and soot are physically difficult for slugs to cross by being either too sharp or by drying up the mucous glands that are necessary for their movement.
- Slug pellets containing metaldehyde are a useful form of chemical control. They work either through being eaten or by contact with the slug or snail's skin. Metaldehyde is an irritant that causes the slug to produce masses of mucus, leading to dehydration which can take a day or more to kill the slug. If, during this interval, there is rain, or even heavy dew, slugs can replace the water they have lost and make a full recovery. Make sure you remove all poisoned slugs and snails as soon as possible to prevent birds and other wildlife from eating them and also being harmed by the poison. Always follow the manufacturer’s guidelines when applying any treatment.
- Soil rotovation in early spring is one of the best of all slug controls. Three passes with a rotovator across an area of soil should reduce slug numbers considerably. This can therefore be more effective than any of the chemical treatments. Choose a time when the weather is warming up, to ensure that the slugs are at or near the soil's surface. Rotovating the soil both physically kills slugs and also exposes them and their eggs to predators and the weather. Digging by hand will have the same result to a lesser extent, and may be necessary where rotovating is inappropriate.